The present invention relates to devices for preventing sleeping or dozing of equipment operators such as vehicle drivers, to massaging devices, and to devices for communicating equipment functional conditions to operators thereof.
Sleep prevention devices are known, being disclosed for example in U.S. Pat. Nos. 3,938,123 to Warner, 4,023,098 to Muncheryan, 4,059,830 to Threadgill, 4,354,179 to Fourcade, and 5,585,785 to Gwin et al. The Warner patent discloses headgear having a battery-powered buzzer that sounds with increasing intensity until the wearer shakes his head. The Muncheryan patent discloses a dash-mountable circuit unit having a rheostat connected in series with battery power and a pair of output jacks, and a toggle switch for selectively disconnecting the power or connecting an interrupter in series with the power. The Threadgill patent discloses electrical contacts that are worn on adjacent fingers and biased toward contact for closing a circuit when the user relaxes, the circuit activating a buzzer or other stimulator for awakening the user. The Fourcade patent discloses an ear prosthesis having an adjustable mercury switch that closes an alarm circuit when the user's head reaches an abnormal inclination. The Gwin et al. patent discloses a force-sensitive transducer that variably feeds a microprocessor, the microprocessor activating an alarm when the force falls below a low limit that is established in an initial period of operation. Also proposed, but not described, is monitoring of transient behavior in a manner used for monitoring steering wheel oscillations. The above devices are unsatisfactory for a number of reasons. For example:
1. The headgear of Warner requires unnatural repetitive head motion to prevent false alarms; PA1 2. The ear prosthesis of Fourcade is ineffective in that sleep can occur in normal head orientations, and false alarms can result from vehicle accelerations; PA1 3. The device of Muncheryan is ineffective for improving or maintaining a driver's alertness in that uniform vibration and regular interruptions of vibratory action promote habituation, the vibratory action being progressively ignored by the user, and it is believed that relaxation by regular massaging of a limited fixed set of muscle groups only at reduced intensity tends to promote drowsiness; PA1 4. The Threadgill device is awkward to use in that the user must actively and continuously force his fingers apart; and PA1 5. The Gwin et al. system is ineffective in that a driver can set an abnormally low threshold by intentionally using very little force during the first 15 seconds of operation; also, it is believed that there is no enabling disclosure of the use of transients in measured gripping force for detecting drowsiness. PA1 (a) providing a plurality of vibratory transducers in plural zones of a driver's seat, a driver circuit connected to the transducers and having respective inputs for receiving corresponding drive signals, and a controller for producing the drive signals, the controller having an alert input; PA1 (b) activating the alert input; PA1 (c) operating the controller to produce the drive signals, in response to the alert input, in alert stimulation cycles of sufficient duration, frequency, and intensity for selectively stimulating muscle groups of the driver; and PA1 (d) sequencing plural cycle segments of the alert stimulation cycles, successive cycles varying in at least one of intensity, frequency, and transducers enabled, thereby to improve the driver's alertness.
Typical warning systems of the prior art use visual or auditory indications of sensed conditions for initiating appropriate human responses in the nature of corrective action. For example, vehicle fuel gauges are commonly provided with warning lights that are activated when the supply reaches a low threshold, and aircraft have audible warnings of dangerous conditions such as an impending stall at low speed. Visual indications are often ineffective when used alone, in that they might not be noticed. Auditory indications can be ineffective in noisy environments, particularly when the user is hearing-impaired, and they can be objectionable when the indication does not require immediate corrective action.
Recent developments in massaging apparatus have produced a variety of products incorporating plural vibration transducers that operate in multiple modes. However, none is particularly suited for improving or maintaining a driver's alertness as desired for the reasons discussed above.
Thus there is a need for a tactile alert system that overcomes the disadvantages of the prior art, and that is reliable, easy to operate and inexpensive to produce.